1. Field of the Invention
The present invention relates to an image-forming apparatus such as a display apparatus using an electron beam, and a method of manufacturing the same.
2. Related Background Art
Conventionally, as an image-forming apparatus using electron-emitting devices, a plane type electron beam display panel is known in which an electron source substrate with a number of cold cathode devices formed thereon and an anode substrate provided with anode electrodes and phosphors are opposed to each other in parallel, and an inside thereof is exhausted to a vacuum. For example, U.S. Pat. No. 5,066,883 and the like disclose such an image-forming apparatus using surface conduction electron-emitting devices. A plane type electron beam display panel using surface conduction electron-emitting devices can be rendered light-weight and have a large screen, compared with a cathode ray tube (CRT) that is widely used at the present. Such a plane type electron beam display panel can also provide a higher quality image with higher brightness, compared with other plane type display panels such as a plane type display panel using liquid crystal, a plasma display, and an electroluminescent display.
In a conventional plane type electron beam display panel as an exemplary image forming apparatus using electron-emitting devices, a vacuum container is composed of a rear plate, a face plate, and a side wall (supporting frame). Electron-emitting devices are provided on an electron source substrate of the rear plate, and phosphors and anode electrodes (metal back, etc.) are provided on the face plate, in such a manner that one phosphor corresponds to one electron-emitting device. Furthermore, the electron-emitting devices are connected to row-directional wirings and column-directional wirings. In the electron beam display panel with the above-mentioned structure, in order to accelerate electrons emitted from an electron source, a high voltage (Va) of about hundreds of V to several kV or more is applied between the rear plate and the face plate. The brightness of the image-forming apparatus substantially depends upon Va, so that it is required to increase Va in order to obtain high brightness. However, when Va is increased, discharge may occur in the image-forming apparatus. Particularly, in the case where spacer members are disposed in the image-forming apparatus for the purpose of keeping a predetermined interval between the rear plate and the face plate and of supporting the plates against an atmospheric pressure, and in the case where getter members are disposed for the purpose of maintaining a high vacuum state, an electric field is likely to be concentrated in the vicinity of these spacer members and getter members, which may cause discharge.
Furthermore, in the structure in which a supporting frame is disposed in the vicinity of anode electrodes so as to miniaturize the image-forming apparatus, surface creepage may occur via the surface of the supporting frame.
The above-mentioned discharge suddenly occurs during an image display, which may not only disturb an image but also remarkably degrade the electron source in the vicinity of a discharge portion. Accordingly, there is a possibility that a display may not be conducted normally.
Therefore, with the foregoing in mind, it is an object of the present invention to provide a highly reliable image-forming apparatus that prevents the concentration of an electric field and the occurrence of surface creepage caused by an apparatus configuration, and remarkably reduces damage caused by discharge so as to prevent breakage of the apparatus even in the case where discharge occurs in the apparatus using an electron source, and a method of manufacturing the same.
The present invention relates to an image-forming apparatus in which a rear plate with an electron source disposed thereon and a face plate having an image-forming region that is irradiated with electrons emitted from the electron source to form an image are opposed to each other to constitute a vacuum container.
An image-forming apparatus of the present invention includes: a vacuum container constituted by disposing in opposition to each other a rear plate provided with an electron source formed and a face plate having an image display region provided with at least phosphors for being irradiated with electrons emitted from the electron source to form an image and anodes disposed on the phosphors; anode potential supplying means for supplying to the anode an electric potential higher than that of the electron source; at least one electroconductive member provided at a site outside of the image display region on an inner surface of the face plate; potential supplying means for supplying an electric potential between a lowest electric potential of those which are applied to the electron source and an electric potential applied to the anode to the electroconductive member; and first and second resistant members having a resistance higher than that of the anode and having different resistances from each other, electrically connected between the anode and the electroconductive members, wherein the anode, the first resistant member, the second resistant member, and the electroconductive member are electrically connected in series.
Furthermore, according to another structure of the present invention, an image-forming apparatus includes: a vacuum container constituted by disposing in opposition to each other a rear plate provided with an electron source formed thereon, and a face plate having an image display region that is provided with at least phosphors for being irradiated with electrons emitted from the electron source to form an image and anodes disposed on the phosphors; anode potential supplying means for supplying to the anode an electric potential higher than that of the electron source; at least one electroconductive member provided at a site outside of the image display region on an inner surface of the face plate; potential supplying means for supplying an electric potential at a level between a lowest electric potential of those which are applied to the electron source and an electric potential applied to the anode to the electroconductive member; and a resistant member with a resistance higher than that of the anode, electrically connected between the anode and the electroconductive member, wherein the resistant member is composed of a first resistant member having a sheet resistance R1 on a side closer to the anode, and a second resistant member having a sheet resistance R2 on a side closer to the electroconductive member, the first resistant member and the second resistant member are electrically connected in series from the anode to the electroconductive member, and R2 is larger than R1.
Furthermore, according to still another structure of the present invention, an image-forming apparatus includes: a vacuum container constituted by disposing in opposition to each other a rear plate provided with an electron source formed thereon and a face plate having an image display region provided with at least phosphors for being irradiated with electrons emitted from the electron source to form an image and anode disposed on the phosphors; anode potential supplying means for supplying to the anode an electric potential higher than that of the electron source; a first resistant member with a resistance higher than that of the anode, provided on an inner surface of the face plate; a second resistant member having a resistance higher than that of the anode and lower than that of the first resistant member, provided in a site outside of the image display region on the inner surface of the face plate; and potential supplying means for supplying an electric potential at a level between a lowest electric potential of those which are applied to the electron source and an electric potential applied to the anode to the second resistant member, wherein the first resistant member is positioned between the anode and the second resistant member, and the anode, the first resistant member, and the second resistant member are electrically connected in series.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.